The effect of wrist position on the conduction velocity of the ulnar nerve

Abstract

Objective: The purpose of this study was to investigate the effect of wrist position on the ulnar nerve conduction velocity. Method: Ulnar motor nerve conduction studies were performed bilaterally in twenty healthy adult volunteers. For each limb, nerve conduction study was carried out in two different positions. In the first position, shoulder were abducted, elbow and wrist flexed to 90. For the second position, all joints were kept constant except for the wrist where it was extended. Routine conduction study was performed in both wrist positions. All data were statistically analyzed. Results: The average conduction velocities in the wrist flexed position were 61.6 m/sec for the forearm segment and 62.3 m/sec across elbow. With the wrist extended, the average was 62.6 m/sec and 64.1 m/sec, respectively. The differences in conduction velocities between two different wrist positions were statistically significant (p＜0.05). In the wrist flexed position, the average measured latencies were 2.3 msec with wrist, 5.4 msec below elbow, and 7.4 msec above elbow stimulation, compared to wrist extended which showed 2.4, 5.4 and 7.2 msec, respectively. The difference of latencies at wrist between the two wrist positions was statistically significant (p＜0.05). Conclusion: The authors conclude that wrist position affect ulnar nerve conduction velocity.